With increasing interest in thin-film devices, flexible electronics, and three-dimensional integration schemes, techniques have been developed to transfer thin-film device layers from a growth substrate with one set of characteristics desirable for growth of the device layers, such as a particular lattice parameter or a particular crystallographic orientation, to an alternate, device substrate with another set of characteristics desirable for the intended application, such as high flexibility or high thermal conductivity. Traditionally, wafer bonding and grind or etchback techniques have been used to achieve this goal. Though effective, these techniques can significantly add to resource consumption and fabrication cost, as a growth substrate can be substantially consumed as a result of grinding or etchback. Certain thin-film device layer transfer techniques, such as thin-film lift-off, can allow device layer removal while leaving a growth substrate intact for reuse. However, the resulting freestanding device layers can be difficult to manipulate for subsequent bonding to a dissimilar, device substrate. Other thin-film device layer transfer techniques, such as Cleavage of Lateral Epitaxial Films for Transfer (“CLEFT”) and Electronic Layer Transfer (“ELTRAN”), exploit mechanically weak layers to facilitate device layer transfer to an alternate, device substrate. Unfortunately, these techniques can suffer from certain deficiencies that limit their applicability. In particular, device layer transfer by the CLEFT technique can be restricted to the use of growth substrates having a particular crystallographic orientation, while the ELTRAN technique can be restricted to a particular lattice parameter related to silicon homoepitaxial or pseudomorphic growth.
It is against this background that a need arose to develop the composite semiconductor substrates and related devices and methods described herein.